1. Field of the Invention
The present invention relates to a recording apparatus such as a copying machine, a printer and the like, and a sheet convey apparatus used with such recording apparatus.
2. Related Background Art
An example of a conventional copying machine is shown in FIG. 19. In this copying machine, a plurality of recording sheets 551 are stacked in a cassette 552 which is removably mounted to a body 553 of the copying machine. The machine body 553 is provided with a sheet supply roller 554 for feeding out the recording sheet 551, a pair of guide 555, 556, a recording portion 557, and a pair of sheet discharge rollers 558. The pair of guides 555, 556 are arranged in an opposed relation to constitute a convey path for the recording sheet 551. The pair of discharge rollers 558 are arranged in the proximity of an outer cover of the machine body 553, and a tray 559 is arranged below and in the proximity of the paired discharge rollers 558. The tray has a length substantially same as a maximum length (Li in FIG. 19) of the recording sheet 551 contained in the cassette 552.
In a recording operation, the recording sheet 551 is fed out from the cassette 552, and an image is formed on the recording sheet at the recording portion 557, and then the recording sheet is discharged onto the tray 559 disposed outside the machine by the pair of discharge rollers 558.
In the above-mentioned conventional copying machine, since the pair of discharge rollers 558 are arranged in the proximity of the outer cover of the machine body 553, the tray 559 is protruded from the copying machine. Thus, even if the copying machine is made small-sized, since the tray is protruded from the machine, the substantial installation space for the copying machine will be increased by the length (Ll) of the tray. Further, since the discharge recording sheets are left on the tray (out of the machine) as they are, the sheets may be dropped from the tray by the air wind from an air conditioner or the imaged contents of the copies may be stolen by other persons or, when ink is used in the recording portion, the image on the copy may be deteriorated by the next discharged copy.
Another example of a conventional copying machine is shown in FIG. 20. In this copying machine, a plurality of recording sheets 600 are stacked in a cassette 601 which is removably mounted to a body 602 of the copying machine. Within the machine body 602, there are arranged a sheet supply roller 603 for feeding out the recording sheet 600, a pair of guides 604, 605, a recording portion 606, and a pair of sheet discharge rollers 607. The pair of guides 604, 605 are arranged in an opposed relation to constitute a convey path for the recording sheet 600.
The pair of discharge rollers 607 are arranged in the proximity of a discharge port 608 of the machine body 602, and a tray 609 is arranged below and in the proximity of the paired discharge rollers 558 and outside the copying machine. A protruded amount of the tray 609 is substantially the same as a maximum length (A in FIG. 20) of the recording sheet 600 contained in the cassette 601.
In a recording operation, the recording sheet 600 is fed out from the cassette 601, and an image is formed on the recording sheet at the recording portion 606, and then the recording sheet is discharged onto the tray 609 disposed outside the machine by the pair of discharge rollers 607. However, since the tray is protruded outwardly from the copying machine, the tray is a hindrance to an operator, and since the sheets may be dropped from the tray by the air wind, copying machines wherein a tray is arranged within a body of the machine have been proposed. When the tray is arranged within the machine body, since the operator cannot check whether the recording sheets are correctly discharged onto the tray or not, if the recording sheets are discharged out of the tray, the operator is not aware of such abnormity.
A further example of a conventional copying machine is shown in FIG. 21. In this copying machine, a plurality of recording sheets 751 are stacked in a cassette 752 which is removably mounted in an opening portion 753a of a body 753 of the copying machine. The machine body 753 is provided with a sheet supply roller 754 for feeding out the recording sheet 751, a pair of guides 755, 756, a recording portion 757, and a pair of sheet discharge rollers 758. The pair of guides 755, 756 are arranged in an opposed relation to constitute a convey path for the recording sheet 751. Further, the machine body 753 is divided into two parts one of which (753b) can be opened.
In a recording operation, the recording sheet 751 is positioned at a convey position 759a in the cassette 752, and, when the recording operation is started the recording sheet is conveyed in a direction shown by the arrow by the sheet supply roller 754, and is U-turned at a convey position 759b defined by the guides 755, 756, and then is sent, through a convey position 759c formed above the cassette 752, to the recording portion 757, where an image is formed on the recording sheet, and then the recording sheet is discharged out of the copying machine by the pair of discharge rollers 758.
When the sheet jam treatment is effected, the cassette 752 is firstly retracted toward the left (in FIG. 21), and then the jammed recording sheet 751 is removed after the body part 753b is opened. However, since the recording sheet convey path is disposed above the cassette, it is difficult to perform the sheet jam treatment. That is to say, if the sheet is jammed, the sheet will remain in the convey position 759a, 759b or 759c. If the sheet is jammed in the convey position 759b or 759c, the jammed sheet can be removed after the body part 753b and the guide 756 defining an upper wall of the convey position 759c are opened. However, if the sheet is jammed in the convey position 759a, it is very difficult to remove the jammed sheet, because, when the cassette 752 is retracted, the uppermost recording sheet is caught by the sheet supply roller 754 so that the uppermost sheet comes out the cassette to be left in the convey position 759a. Further, in the normal sheet supplying operation, the poor sheet supply condition often occurs due to the slip between the recording sheet 751 and the sheet supply roller 754, thereby remaining the recording sheet 751 in the convey position 759a.
In such cases, even when the cassette 752 is retracted, the remaining recording sheet cannot be removed. The reason is that, in order to make the machine small-sized, since the opening portion 753a only has a space required for mounting and dismounting the cassette, the operator cannot insert his hand in the opening portion to remove the jammed recording sheet.
In particular, recently, in order to make the machine small-sized, the copying machines have been designed so that the cassette 752 is contained in the machine body 753. In such copying machines, if the recording sheet is jammed or if the sheet is jammed when recording sheets of small size are contained in a universal cassette capable of accommodating various sizes of sheets, since the convey position 759a is positioned deeper in the machine body, the removal of the jammed recording sheet will be further difficult.
Further, since the guide 755 is integrally formed with the machine body 753 to reduce the number of parts, even when the part body 753a and the guide 756 are opened, the operator cannot see the recording sheet in the convey position 759a, thus making the removal of the jammed sheet difficult. In this case, the operator cannot ascertain whether the sheet is jammed or not, and, accordingly, if the cassette is inserted again while the sheet is being jammed, the serious trouble will occur.
The other example of a conventional copying machine is shown in FIGS. 22 and 23. In FIGS. 22 and 23, first of all, a recording portion will be explained. A plurality of recording sheets 851 are stacked in a container case 852. The recording sheets are fed out by a convey roller 853 and are separated one by one by a separation member 854. The separated recording sheet is conveyed in a direction shown by the arrow a. Then, the recording sheet 851 is guided by the convey rollers 853 and a recording guide 855 to be sent to a recording portion while being reversed or turned up.
A carriage 857 is shifted in a direction perpendicular to the plane of FIG. 23 along a guide 856. An ink cartridge 858 is removably mounted on the carriage 857 and serves to discharge ink to form an image on the recording sheet 851 in response to an image signal upon the reciprocal movement of the carriage 857. The ink cartirdge 858 integrally includes an ink discharge portion, an ink supply portion, an ink heating portion, and an ink tank.
As shown in FIG. 25, recording sheet side guides 859 are pivotally supported for rotational movements in directions shown by the arrows d, respectively, so that the recording sheet 851 on which the image was formed is conveyed in a direction shown by the arrow b while being supported at both lateral edges. This is the reason that the ink droplets discharged from the ink cartridge 858 on the recording sheet 851 are not immediately solidified on the recording sheet, and if the non-solidified ink droplets are rubbed by a tip end 851a of the recording sheet 851, the quality of the image will be worsened. Thus, the tip end 851a of the recording sheet on which the image is being formed is guided by the side guides 859 so that the image formed on the recording sheet 851 is not rubbed by the tip end of the next recording sheet. When the image forming operation is finished, as shown in FIG. 26, the recording sheet side guides 859 are rotated in the directions shown by the arrows d, and the sheets are stacked on the recording sheet stack 851 already rested on a recording sheet discharge tray 860.
Next, a reading portion will be explained. In FIG. 23, one or more originals 861 to be read are rested on an original stacking tray 862, and lateral edges of the originals are positioned by original width guides 863, and the originals are inserted into the copying machine from this side (right in FIG. 23) to that side (left in FIG. 23). When a reading operation is started in response to the command from an operation panel 864 arranged on an upper surface of the machine body, a separation roller 865 is rotated in a direction shown by the arrow e, and the originals are separated one by one from the lowermost one by a separation member 866. The separated original 861 is sent to a reading portion by a pair of convey rollers 867, 868. In the reading portion, the original is set within the depth of focus of a reading sensor 870 by a sensor roller 869. The image data on the original is read by the sensor 870 by the photo-electric conversion technique. Then, the original is conveyed in a direction shown by the arrow c by a pair of discharge rollers 871, 872 to be discharged onto an original discharge tray 873.
Now, when the ink cartridge 858 is desired to be exchanged by a new one due to the poor ink discharge from the cartridge, such exchanging operation will be explained with reference to FIG. 24. First of all, the operator rotates a recording cover 874 on which the original stacking tray 862 and the original width guides 863 are provided around a hinge means 875, thereby inclining the cover toward this side of the machine. As a result, the upper portion of the recording portion of the copying machine is opened. In this condition, the ink cartridge is removed from the copying machine by picking up the cartridge from the above, and a new ink cartridge is inserted into the copying machine. Then, the recording cover 874 is rotated toward that side of the machine around the hinge means 875, thereby closing the recording portion.
However, in the above-mentioned conventional copying machine, as shown in FIG. 23, since a space shown as an area A above the recording sheet side guides must include a space required for accommodating a predetermined number of recording sheets 851 and a space sufficient to prevent the deterioration of the image while conveying the recording sheet on which the non-solidified ink droplets were discharged, the copying machine becomes large-sized.
Further, if the recording sheets 851 more than the predetermined number are stacked on the recording sheet discharge tray 860, the next sheet is likely to be jammed due to the presence of the discharged sheets (particularly, in a facsimile system which is being operated all night without no monitor, if a large amount of data are received, such sheet jam will frequently occur).
Further, after reading, when the originals 861 are remained on the original discharge tray 873 (particularly, in the facsimile system, the read originals 861 are often remained on the original discharge tray 873 for the memory transmission, timer transmission and the like), it is difficult for the operator to see the imaged surfaces of the recording sheets 851 discharged on the recording sheet discharge tray 860.